Declares a variable which is shared between code modules. A matching Common statement must appear in all other code modules using the variable.

Common variables cannot be initialized.Common arrays are always variable-length, and must be defined with an empty parameter list (), and its dimensions set in a later Dim or Redim statement.Common variables cannot be instances of a user-defined type having a constructor or a destructor even implicit.

The Shared optional parameter makes the variable global so that it can be used inside subs and functions, as well as at module level.